1. Field of the Invention
This invention relates to an arena floor useful alternately as a support for artificially frozen ice and as a deck suitable for various activities to be practiced without the presence of ice, such as gymnastics and various games, said floor being composed of a plurality of elongate board-like elements placed and held together in parallel side by side relationship on a supporting bed. In said floor each of said elements has a width which is several times greater than the height thereof and presents a plurality of laterally spaced and longitudinally extending passages for enabling circulation of a temperature-controlling fluid therethrough. Furthermore the invention relates to an elongate element suitable for use in composing such an arena floor, said element being made of extruded plastic, i.e. a synthetic resin material, and comprising a substantially solid and panel-like upper body portion forming a generally flat element top surface, and integral therewith a lower body portion forming bottom and side wall members of the element passages.
2. Description of the Prior Art
For decades it has been known to provide, outdoors as well as indoors, artificially frozen ice rinks for skating and for practicing various ice games, such as hockey, curling and the like, Basically this is accomplished by circulating a frigid fluid, such as a brine or a glycol-water mixture, cooled by some sort of heat pump unit, through a more or less complex system of pipes spread out over the area selected for being iced and by watering said area in a manner to build up an ice slab thereon. Usually the average temperature of the fluid passed through the pipe system is then kept between about 8.degree. C. and 12.degree. C. below zero.
After some time of use the top layer of such an ice slab will become worn and uneven and hence in need of restoration. At least as far as large-sized rinks are concerned this is commonly carried out by means of fairly heavy, wheeled and self-propelled ice-restoring machines which are adapted to plane the top of the ice slab and to distribute a small amount of water thereover which when frozen will form a fresh and at least substantially dentfree top layer on the ice slab.
In order to assure maximum operating economy of an ice rink of the kind referred to it is advisable to support the ice slab on a bed which has a fairly high heat insulating capacity so that cooling of the sub-structure, e.g. the ground, is minimized or at least reduced. Also, for best operating economy, it has been found desirable to limit the thickness of the ice slab to about 5 centimeters or even less. However, with such a moderate thickness the ice slab will have an objectionable tendency to crack, especially under the loads of the heavy and moving ice-restoring machines, unless the floor and the bed is firm enough to resist any substantial local yielding.
For this reason it has been common practice either to embed the pipes for the circulating cooling fluid in grooves provided in a hard top layer of the bed, or to simply place the pipes directly on top of a hard bed surface so that they will instead be embedded in the ice itself. Some suggestions have also been made that the pipes or passages for the cooling fluid should be combined with rigid metal panels which when held together in edge to edge relationship can form a complete and hard deck on top of the bed. However, practice has proved that the installation of such a deck is very difficult because, for various obvious reasons, the metal panels can only be given fairly moderate dimensions, and hence a tremendous number of fluid couplings is needed to fit them together. Also each such coupling represents a leakage hazard if not very carefully made.
Now, in many cases ice rinks are needed only during certain seasons or even shorter periods, and it is then desirable to use the area occupied by the ice for various other activities in between. Since ice rinks are most frequently arranged within sport grounds or halls, it is most likely that such other activities will be gymnastics and various ball games which do not only require a fairly flat and smooth floor but should preferably be practiced on a surface which is at least slightly elastic and yielding. Accordingly, in case the bed for the ice has the fluid pipes embedded in grooves it will at least be necessary to cover it with a separate, fairly thick mat, which must be removed before the area is again iced, and in case the fluid pipes are placed on top of the bed these pipes must first be removed before a suitable mat can be spread out and the again be properly distributed over the area after removal of the mat before the bed can again be used for supporting a layer of ice. Also when prefabricated metal panels of the kind referred to above are used it will at least be necessary to place a suitable mat on top of them.
Considering that most ice rinks have areas exceeding more than one thousand square meters, it will be obvious that the work needed to change each of them into an arena suitable for gymnastic or other activities requiring a relatively soft floor surface will be tremendous even with the most convenient forms of the prior art structures so far used. In addition, considerable space will be needed for storing the mats, or the pipe system, temporarily to be removed.
Accordingly, there is an obvious need for an improved arena floor which can be permanently installed on top of a firm, heat-insulating bed and alternately serve as a practically non-yielding support for artificially frozen ice produced by circulating a cooled fluid through passages formed in the floor itself and, after removal of the ice only, as a more or less elastically yielding deck, the softness of which may even, if so needed or desired, be adjusted by instead circulating a warm fluid through said passages, it being understood that such a warm fluid may also assist in rapidly melting away the ice.